1. Field
This disclosure relates to a positive electrode for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery.
2. Description of the Related Technology
Recently, a lithium nickel composite oxide including nickel has been suggested as a positive active material capable of achieving a high potential and high capacity in a rechargeable lithium ion battery.
For example, JP 2001-167761 discloses a technology of improving cycle characteristics by using LiMeO2 having a (I003)/(I104) ratio of a diffraction peak intensity (I003) at a (003) plane and a diffraction peak intensity (I104) at a (104) plane in the X-ray diffraction in a range of greater than or equal to about 1.5 to less than or equal to about 4 (herein, Me is at least one selected from Ni and Co) as a positive active material.
In addition, JP 2013-120676 discloses a technology of improving battery characteristics by using LixNi1-yMyO2+a having less than or equal to about 0.80 of a diffraction peak intensity ratio (104/003) of (104) and (003) planes in the X-ray diffraction as a positive active material.
Patent Laid-open: JP 2001-167761
Patent Laid-open: JP 2013-120676
JP 2001-167761 and JP 2013-120676 describe suppression of Ni ions from being mixed into Li sites in a crystal (so-called, a cation mixing phenomenon) and stabilize the crystalline structure by increasing a ratio of diffraction peak intensity at the (003) plane relative to diffraction peak intensity at the (104) plane in the X-ray diffraction. However, when a lithium nickel composite oxide having a high Ni ratio is used as the positive active material to manufacture a rechargeable lithium ion battery having a high potential and simultaneously, high-capacity, structural stability of the positive active material is deteriorated as the Ni ratio increases.
Accordingly, disclosures of JP 2001-167761 and JP 2013-120676 have a problem of destabilizing the structure of the positive active material, deteriorating cycle characteristics, and initial charge and discharge efficiency of the rechargeable lithium ion battery.